Telecommunications networks today are becoming more flexible and agile. For example, technologies such as reconfigurable optical add drop multiplexers and optical cross-connects enable 2.5, 10 Gigabit, and 40 Gigabit per second dense wave division multiplexed service channels to be switched virtually instantaneously from one pair of endpoints to a different endpoint under management software control. Technologies such as the Virtual Concatenation and Link Capacity Adjustment enable Synchronous Optical Network (SONET) bandwidth layer channels to be incremented or decremented by relatively fine grained STS-1 increments in services such as Optical Mesh Service, available from AT&T, Inc., of San Antonio, Tex. Multi-protocol Label Switching (MPLS) enables specification of specific routes through Virtual Private Network (VPN) Routing and Forwarding (VRF) tables, and alternate specific routes through MPLS Fast Reroute capability. MPLS also offers Quality of Service control, where, briefly, different packets traversing an MPLS network are given higher or lower priority for transport, and therefore experience different average latency in transmission. Also, technologies such as the Intelligent Routing Service Control Point (IRSCP), also available from AT&T, provide very fine grained route control and packet control at the IP layer. For example, a specific flow, comprising a given source IP address, destination IP address, and port number, may be sent to the destination along a specific route, and/or specific packets in the flow may be dropped, quarantined, or forwarded according to that header information.
In summary, a variety of technologies built into current and evolving telecommunications network equipment, or provided by telecommunications service providers, enable much greater flexibility and control than traditionally has been the case in what may be generally referred to as route control, bandwidth control, packet control, and quality of service (QoS) control. Route control is the ability to specify a sequence of nodes or hops for transported traffic to take. Bandwidth control is the ability to increment or decrement the capacity of a network link to carry traffic. QoS control is the ability to specify priority treatment of packets. Packet control is the ability to specify differential treatment of packets based on characteristics of the packet.
Separately, Wide Area Network (WAN) acceleration or application acceleration appliances are coming on the market. These include the Wide Area Acceleration System (WAAS), from Cisco systems of San Jose, Calif., as exemplary of a class of appliances that attempt to enhance performance of distributed applications used across a wide area network through a variety of techniques. One such technique is to cache recently accessed content at the edge, so that it may be accessed again locally without resorting to the Wide Area Network usage. Similar techniques include predictive caching and also protocol spoofing, that is, reducing the “chattiness” of protocols used by common applications such as Excel and Word from Microsoft Corporation of Redmond, Wash., by “fabricating” local responses rather than require a large number of synchronous responses that need to occur via transactions carried (slowly, relative to a Large Area Network (LAN)) over a Wide Area Network.
Finally, a group of technologies such as are available from Packeteer and Ipanema conduct what may be referred to as edge shaping, where a pair of appliances at a source and destination location may be used, in combination with a policy control layer, to prioritize traffic from one application over that arising from another. Such shaping can include dropping packets from the lower application.
As discussed above, various approaches, such as, WAN flexibility through route, bandwidth, packet, and QoS control, WAN acceleration through edge caching, edge shaping etc., are available to fulfill the application performance requirements. When faced with a variety of potential approaches, one is faced with an issue of what is the best strategy for a given application mix, that is, rather than a single monolithic application, a mix of applications such as voice over data, e.g., Voice over IP, video, application data, file transfer, storage applications such as mirroring and replication, etc. For example, if the transaction rate increases, one is faced with a point in question as to what is the better strategy, whether the overall system should increase bandwidth, or should it use shaping to reduce the offered load to the network of that application.
Thus, there is an extreme need to provide a globally optimum solution that leverages available approaches to best meet application performance requirements.